I believe Emilio might be alluding to the fact that the Rotrex's large compressor wheel, much like a large turbo with a large compressor wheel, generally creates less heat at similar flow rates than a smaller one. And most turbos used on Miatas have smaller compressor wheels than that found on the Rotrex.

But I don't want to put words in Emilios mouth. That's my impression.

 

All this Rotrex talk has me thinking dirty about my time trial car...must resist temptation. No one sells a bare bones kit with only the blower, bracket and oil system for the blower, correct?

 

I thought in a time trial car you wanted a very strong torque curve without too much peak HP - a flat HP curve, if you will.

 

For a car that is NASA PT I don't doubt it looking at the dyno plots for some cars. My car is for Miata Challenge/ridiculous street car so I'm entertaining different options. I have a second chassis I am using for a SuperMiata for some W2W action.

 

A little of both but mostly blower outlet temps. It's not difficult to build a turbo system to sustain IAT's of 115° just like a Rotrex.

The difference is the raw outlet temps and how much intercooling is required to get to that IAT and where in the RPM range that peak compressor efficiency is.

Looking at the point where cylinder pressure should be the highest, a 300whp turbo might be 4800rpm. The 300whp turbo system will be generating a bunch more torque at 4800 and commensurately higher cylinder pressures (det potential).

The natural VE peak of a stock BP is usually around 6200rpm, where the Rotrex is basically at peak torque when geared for a 7000rpm redline. The VE peak falls off enough after that to reduce torque even though the blower is making more boost. The difference here is that the equivalent Rotrex is hitting its peak efficiency there so it requires the least intercooling. This is how a Rotrex blower at 13-16psi can match the same size turbo at 18-21psi for peak power. Also why we can run 300whp in a Rotrex with stock ignition timing. It's possible to match efficiency of a Rotrex with a turbo but it requires a compressor with a much greater CFM capacity than is required for target whp with its corresponding lag.

Turbos obviously kick *** on track. They are just more expensive and involved to make reliable than a Rotrex making the same peak power. Unless you have a TSE turbo kit like I do.

 

<3

 

^949Racing - All the win resides within.

 

This thread on Miataturbo.net about a nasty n/a BP has really only made me want to get rid of my 2554 in favor of a c30-94.

The ironing.

 

If you are serious about the C30-94 comment, then check out Track Dog Racing's upcoming kit. I went there personally two weeks ago and got a ride in the shop car with 300+ whp. It was incredibly fun and their mounting bracket is way stronger than the Kraftwerks piece. I got to compare them side-by-side.

 

Yep very serious. Depending on how much out of pocket it'll hit after selling turbo setup.

 

TRD bracket looks nice but they are running 4-rib from the ps/ac belt which will never work. Even 6-rib will slip on track. It needs a dedicated 8-rib setup with a C38 Rotrex placed in the AC compressor location.

 

Time for a separate Rotrex thread

 

cxracing.com: CXRacing Performance Header For 89-99 Miata MX-5 NA 1.8L Equal Length Long Tube
So when are you guys dynoing this abomination :v

 

The sad thing is I would kill for KL headers like that.

 

We bought a CX header to look at and dyno. It is far uglier in the flesh. Comically bad actually. Ill post pics after we dyno it.

We are dropping the Whammy into the 95R this week with a Racing Beat. Ocean tells me my Maruha will not be here until mid June.

 

I am willing to bet that bundle of snakes won't do ****. Equal length is great but not at the expense of having the exhaust gases change direction like that.

I bet the RB is gonna be real close to the Mahara and that CXR last by a good margin.

 

Probably.

 

But the CX Racing header according to the site was "fully tested" so it must be good right? Also listed as "easy installation", which with a v band outlet must be super simple to install for the average joe.

 

My favorite part is that it fits the 89-99 1.8 engine. That's not confusing at all.

 

No it fits the 1.8 engine in the 89-99 chassis. Even though it would fit the 1.8 engine in the 89-05 chassis since it requires a custom mid pipe adapter no matter what chassis you put it in.